Devices for artificially ageing blocks are well known in the art. Some of the prior art included block tumblers; these devices though were inadequate because of the loss of much block material, which raised production costs. Improvements were on-line devices where blocks were conveyed under or through impacting devices for surface modification, deformation, chipping etc. thereof.
Conventional block-conveying systems include a support table for moving the blocks thereon as they are acted on during texture surface modification. The following are examples of block-texture modifying apparatuses.
Canadian Patent Application No. 2,343,338, teaches an apparatus for roughing the surfaces of concrete casted blocks. A roller having chains attached thereon and spaced apart from one another is provided above blocks that are being supported on a moveable table. The support table has a flat upper surface. The support table includes holes through which pins are projected in order to tilt the bottom surface of the blocks hence tilting the whole blocks at predetermined locations in order for the chain to impact the blocks on their upper surface at different locations.
Canadian Patent Application No. 2,350,979, teaches a system for modifying the texture of blocks. The system includes texturing elements that are on support cables which spin and which are brought closer to the block in order to bring the texturing elements in contact with the block for impacting the surface. The texturing elements can be moved at different angles in order to impact the block's surfaces in different areas during the translational movement of the block.
Canadian Patent Application No. 2,392,934, teaches a concrete texture machine for modifying the surface texture of stone blocks. The machine conveys concrete blocks at a pitching station having opposed pitching blades. Each of the blades have a forward projecting cutting edge that are displaced towards and away from one another at predetermined distances.
European Patent Application No. 1211036, teaches a device for artificially ageing stones. This device includes top and bottom rollers with mangling elements that engage the edges stones passed therebetween in order to break and mangles these edges.
A limitation of these prior art apparatuses is that they do not provide for the blocks to be spaced apart at a constant distance when acting on them. Furthermore, these prior art apparatuses are inconvenient for acting on the edges of the blocks.
Japanese Patent Application No. 04194202, teaches a spacer which functions to create a gap between mutual blocks in order to make it look wide in external appearance. The spacer is used for the construction of the blocks. All the documents referred above are included herewith by reference.
The spacers and positioning mechanisms of the prior art are not constructed for modifying pre-cast blocks.
Hence, the prior art teaches chains on a spinning longitudinal member to impact the surface of concrete blocks; rollers for engaging the edges of blocks as well as spacers for building and laying concrete blocks are also known.
A general limitation of the prior art is that is does not provide an apparatus and method for maintaining the block that provides easy access to the block edges so as to act thereon as well as various block-texture modifying actions that modify these edges accordingly.
A drawback of such devices is that high pressure must be applied on these blocks.
There thus remains a need for an improved apparatus and method for modifying the surface texture of blocks.